物料提升计的基础浇筑C20混凝土，厚度不得少于（）。 A.150mm B.200mm

从众型思维枷锁是指在认识判断．解决问题时，附和多数，人云亦云，缺乏自己独立思考，无主见、无创新意识的一种不良思维定势。
以下表现不属于“从众型思维枷锁”的一项是( )。

A．前面许多行人闯了红灯，自己也紧跟着冲了过去
B．大人们把自己孩子的“左撇子”习惯硬性扭转过来
C．专家的意见值得信赖，大家都以专家的意见为办事依据
D．中学生每天都要求穿校服，正在读高中的小军就每天都穿着校服

Read the following text and choose the most suitable heading from A-F for each paragraph. There is one extra heading which you do not need.

PARIS

小题1:Paris, the capital and the largest city of the country, is in north central France. The Paris metropolitan area contains nearly 20% of the nation’s population and is the economic, cultural, and political center of France. The French government has historically favored the city as the site for all decision making, thus powerfully attracting nearly all of the nation’s activities.

小题2:Paris has grown steadily since it was chosen as the national capital in the late 10^th century. With the introduction of the Industrial Revolution, a great number of people moved to the city from the country during the 19^th century. The migration was especially stimulated by the construction of railroads, which provided easy access to the capital. After World War II more and more immigrants arrived.

小题3:The city is the centralized control point of most national radio and television broadcasting. It is a place of publication of the most prestigious (有威望的) newspapers and magazines and an international book publishing center. With more than 100 museums, Paris has truly one of the greatest concentrations of art treasures in the world. The Louvre, opened as a museum in 1793, is one of the largest museums in the world.

小题4:In the late 1980s about 4.1 million pupils annually attended about 47,000 elementary schools. In addition, about 5.4 million students attended some 11,200 secondary schools. Approximately 1.2 million students were enrolled annually at universities and colleges in France in the late 1980s. French centers of learning have served as academic models throughout the world.

小题5:Paris is the leading industrial center of France, with about one quarter of the nation’s manufacturing concentrated in the metropolitan area. Industries of consumer goods have always been drawn to Paris by the enormous market of the big population; and modern, high-technology industries also have become numerous since World War II. Chief manufactures are machinery, automobiles, chemicals and electrical equipment.

若抛物线y=x²﹣x-k与x轴的两个交点都在x轴正半轴上，则k的取值范围是(    )

泰勒提出的科学管理理论的核心是 （）

A.明确的组织分工

B.人是"社会人"

C.提高劳动生产效率

D.职能管理

E.建立严格的纪律

目前国内外评价工程项目经济效果的最普遍、最重要的指标是（）。

A.净现值

B.净收益

C.净现值率

D.内部收益率